The Hematopathology Section of the Laboratory of Pathology, NCI, offers expert diagnostic services in the field of hematopathology. Dr. Stefania Pittaluga, Staff Clinician, and I handle diagnostic service responsibilities equally, each rotating as the staff on service 50% of the time. However, because of the challenging nature of the material we receive for review, and obligations related to specific clinical protocols and teaching conferences, our clinical obligations extend well beyond the designated ?on-service? time. In the past year we were responsible for more than 2200 cases. Dr. Pittaluga oversees triage of clinical samples received by the laboratory, a time consuming activity due to the complicated and sometimes competing demands of clinical protocols. In addition to serving as a Staff Hematopathologist, she assists in supervising the Immunohistochemistry service, and does the laboratory development for new hematopathology tests that are later introduced into the routine test library. She also directs the In Situ Hybridization service. She is supported in these activities by a laboratory technician, and a Post-Baccalaureate fellow. Dr. Pittaluga is also Program Director of the Hematology Fellowship program. Dr. Pittaluga and I provide assistance in the diagnosis and classification of reactive and neoplastic lymphoproliferative disorders, immunodeficiency states, and diverse hematological malignancies. We provide consultative and collaborative services to physicians in the NCI, as well as to physicians studying patients with hematolymphoid disorders in other institutes, in particular NIAID, NHLBI, NHGRI, and NIAMSD. We cosponsor a monthly multidisciplinary case review conference discussing diagnostic or management problems in lymphoma, and in addition regularly present at conferences sponsored by NCI clinical branches (Pediatric Oncology, Medical Oncology, Dermatology, Experimental Transplantation & Immunology), and by NIAID, NHLBI, and NHGRI. We serve as Associate Investigators on more than 40 clinical protocols being conducted in the NCI and other NIH institutes. These protocols frequently mandate specialized testing to characterize the biological markers relevant to the particular study. In collaboration with other service units (Specialized Diagnostics, Cytogenetics, Flow Cytometry), we utilize a variety of diagnostic tools. The Section also provides in situ hybridization services for detection of Epstein Barr viral (EBV) sequences, and other diagnostic and experimental targets. We receive more than 2000 cases in consultation each year. Recent studies have highlighted the importance of secondary review for the diagnosis and proper treatment of patients with lymphoma. 1 Because of the demands that the consultation service places on our time, we try to restrict consultations to difficult or challenging cases. Many cases are submitted by other academic institutions, based on diagnostic uncertainty, or because of differences of opinion among several institutions. We regularly refuse to accept consultations that we regard to be of a routine nature, and recommend that such cases be sent to routine reference laboratories. We frequently make novel observations based on this unique clinical practice, and a number of publications have emanated from case material originally reviewed in consultation. Thus, I believe our clinical work enhances, rather than detracts, from our academic productivity. In many instances consultation cases are submitted to us based on prior publications from our laboratory. These cases contribute to our research mission, as they help us to expand our knowledge of rare entities, and characterize these disorders. Specific examples and the relevant publications are discussed under other projects. However, among them they include in situ follicular lymphoma,2,3 in situ mantle cell lymphoma,4 pediatric follicular lymphoma, pediatric marginal zone lymphomas, NK-cell enteropathy, 5novel variants of peripheral T-cell lymphomas, 6 7-9histiocytic sarcomas arising in B-cell or T-cell malignancies, 10 and plasmacytomas with production of IgA.111.Jaffe ES. Centralized review offers promise for the clinician, the pathologist, and the patient with newly diagnosed lymphoma. J Clin Oncol 2011;29:1398-9.2.Fend F, Cabecadas J, Gaulard P, et al. Early lesions in lymphoid neoplasia: Conclusions based on the Workshop of the XV. meeting of the European Association of Hematopathology and the Society of Hematopathology in Uppsala, Sweden. Journal of Hematopathology in press 3.Jegalian AG, Eberle FC, Pack SD, et al. Follicular lymphoma in situ: clinical implications and comparisons with partial involvement by follicular lymphoma. Blood 2011;118:2976-84.4.Carvajal-Cuenca A, Sua LF, Silva NM, et al. In situ mantle cell lymphoma: clinical implications of an incidental finding with indolent clinical behavior. Haematologica 2011;4:4.5.Mansoor A, Pittaluga S, Beck PL, Wilson WH, Ferry JA, Jaffe ES. NK-cell enteropathy: a benign NK-cell lymphoproliferative disease mimicking intestinal lymphoma: clinicopathologic features and follow-up in a unique case series. Blood 2011;117:1447-52.6.Garcia-Herrera A, Song JY, Chuang SS, et al. Nonhepatosplenic gammadelta T-cell Lymphomas Represent a Spectrum of Aggressive Cytotoxic T-cell Lymphomas With a Mainly Extranodal Presentation. The American journal of surgical pathology 2011;35:1214-25.7.Song JY, Strom T, Raffeld M, Pittaluga S, Jaffe ES. Peripheral T-Cell Lymphoma With Aberrant Expression of CD30, CD15, and CD20. J Clin Oncol 2011.8.Eberle FC, Song JY, Xi L, et al. Nodal Involvement by Cutaneous CD30-positive T-cell Lymphoma Mimicking Classical Hodgkin Lymphoma. The American journal of surgical pathology 2012;36:716-25.9.Menon MP, Jegalion A, Raffeld M, Pittaluga S, Xi L, Jaffe ES. Primary CNS T-Cell Lymphomas: Clinical, Morphologic, Immunophenotypic and Molecular Analysis. Mod Pathol 2012;25:355A-A.10.Shao H, Xi L, Raffeld M, et al. Clonally related histiocytic/dendritic cell sarcoma and chronic lymphocytic leukemia/small lymphocytic lymphoma: a study of seven cases. Mod Pathol 2011;24:1421-32.11.Shao H, Xi L, Raffeld M, et al. Nodal and extranodal plasmacytomas expressing immunoglobulin a: an indolent lymphoproliferative disorder with a low risk of clinical progression. The American journal of surgical pathology 2010;34:1425-35.